Project Summary This proposal is in response to program announcement (PAR-07-352) entitled Bioengineering Research Partnerships (BRP). In this University-Industry Partnership, we are focused on development and testing of diamond-on-diamond and diamond-on-polyethylene surfaces for minimizing wear between articulation components in orthopaedic devices. Complications arising from wear include component loosening, deleterious biological responses, osteolysis, mechanical instability, decreased joint mobility, increased pain, and ultimately implant failure. In this project, UAB and Smith & Nephew, Inc. team up to develop and test unique nanostructured multilayer diamond coatings on metal (CoCrMo or Ti-6Al-4V) orthopaedic devices with the goal of reducing friction and wear in articulation components. We propose a five-year study to focus on the following specific aims: Specific Aim 1: Develop nanotechnology for reducing friction and wear on the articulating, load-bearing components of hip and knee metallic implants by chemical vapor deposition (CVD) of a diamond coating having a multilayer structure with alternating nano- and micro-structural layered components. Specific Aim 2: Demonstrate that the multilayer diamond coatings (intended for diamond-on- diamond or diamond-on-polyethylene articulation) exhibit improved wear resistance when compared to single- layer diamond-on-diamond articulation or to the metal-on-polyethylene or metal-on-metal couples currently used in commercial orthopaedic devices. Specific Aim 3: Perform wear simulator studies involving diamond coated hip and knee articulation components using the industry-standard multi-axis hip and knee simulators located at Smith & Nephew, Inc. Specific Aim 4: Evaluate cellular response to diamond wear debris particles, as compared to polyethylene and cobalt chrome debris particles. Specific Aim 5: Perform in vivo investigations to characterize the initial short term organic and cellular responses of control and diamond biomaterials to overall biocompatibility profiles. Wear debris collected from the tribological studies will be implanted (injected) into the synovial-like air pouch model in the adult rat for short term (hours to days) in order to assess clinical, cellular, histological and cytokine biocompatibility profiles. Implants of discs into trabecular bone regions of rabbits will assess initial tissue fluid and blood interactions with control and coated implant surfaces for time points ranging from hours to months. The overall clinical impact of this proposed BRP would be in improving the service life time of total joint replacements to more than thirty years and hence dramatically reducing the need for recurrent multiple surgical procedures.